Run the DOM Storage layout tests in the UI test framework since the test shell...

Run the DOM Storage layout tests in the UI test framework since the test shell doesn't hit very much of the new code.  I still plan to write unit tests and we're still goign to enable the layout tests in test shell, but this is still a good way for us to test the full stack ASAP.

Workers has used this technique for a while now.  This CL factors out the layout test running code from the workers ui test and moves arounds directories a bit so not everything is in the "workers" directory.

Doing this via a v8 extension is the right way to go long term, but I ran into a couple snags, so I think this is a good first step.

TEST=none
BUG=none

Review URL: http://codereview.chromium.org/159720

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22466 0039d316-1c4b-4281-b951-d872f2087c98